It is well known that edge tools must be maintained in perfect condition in order to work satisfactorily, and although it is well realised that blunt tools are the cause of many accidents because they do not cut freely and properly, the sharpening of edge tools is nevertheless often neglected because of the high degree of skill involved in correctly performing this task. Recently, sharpening guides have become available, which hold the edge tool in a fixed orientation allowing it to be moved over a stationary stone to grind it to a correct shape, but such grinding operation is still laborious and time consuming. Edge tools having curved edges, such as gouges, are almost impossible for the amateur to sharpen properly. Hand-held edge tools are usually supplied by the manufacturer with the edge sharpened by grinding a flat bevel facet at 25.degree. to the opposite major face of the tool, with the very edge of the tool being honed at 30.degree. on a finer stone. Although large scale automatic machinery for grinding the bevel facet and honing the edge of a hand tool are known, equipment available for the owner of a set of hand tools to sharpen these is limited to two basic type the first of which is a guide for use on a stationary flat stone, which is both slow and subject to wear and the second of which is typically shown in British Patent No. 1293729, which describes a pair of rotary grindstones one at each end of a motor shaft in a configuration similar to a conventional bench grinder, in front of which is positioned a tool mount carried on a transverse guide bar extending parallel to the axis of rotation of the grindstones. An edge tool fitted on the mount can then be displaced across the cylindrical surface of one or other of the rotary grindstones and held rigidly in a predetermined orientation whilst being ground. This known tool has the disadvantage that, because it is passed over the cylindrical surface of the grindstone the facet ground on the bevel edge of the tool is concavely curved to form a so-called hollow ground face, which weakens the very edge of the tool and allows it to become blunt more rapidly than a flat edge. There is also the possibility that a variation in pressure applied by the user as the edge tool is traversed across the grindstone will result in differing amounts of material being removed from the edge of the tool at different transverse positions so that a straight true edge is not guaranteed, especially for wider tools such as plane irons. In an attempt to overcome this problem the tool holder described in European Patent application No. 225806 incorporates a stop member for limiting the rotation of a tool holder about a tool guide formed as a cylindrical bar, but this tool too provides a bevel facet which is hollow ground and, furthermore, involves considerably complexity in the tool mount.